Add stream terminate event

- Send from Deribit connection

apps/tai/lib/tai/events/stream_terminate.ex

@@ -0,0 +1,22 @@
+defmodule Tai.Events.StreamTerminate do
+  alias __MODULE__
+
+  @type venue :: Tai.Venue.id()
+  @type t :: %StreamTerminate{venue: venue, reason: term}
+
+  @enforce_keys ~w(venue reason)a
+  defstruct ~w(venue reason)a
+end
+
+defimpl TaiEvents.LogEvent, for: Tai.Events.StreamTerminate do
+  def to_data(event) do
+    keys =
+      event
+      |> Map.keys()
+      |> Enum.filter(&(&1 != :__struct__))
+
+    event
+    |> Map.take(keys)
+    |> Map.put(:reason, event.reason |> inspect)
+  end
+end

apps/tai/lib/tai/venue_adapters/deribit/stream/connection.ex

@@ -75,6 +75,10 @@ defmodule Tai.VenueAdapters.Deribit.Stream.Connection do
   @spec to_name(venue) :: atom
   def to_name(venue), do: :"#{__MODULE__}_#{venue}"
 
+  def terminate(close_reason, state) do
+    TaiEvents.error(%Tai.Events.StreamTerminate{venue: state.venue, reason: close_reason})
+  end
+
   def handle_connect(_conn, state) do
     TaiEvents.info(%Tai.Events.StreamConnect{venue: state.venue})
     send(self(), :init_subscriptions)

apps/tai/test/tai/events/stream_terminate_test.exs

@@ -0,0 +1,16 @@
+defmodule Tai.Events.StreamTerminateTest do
+  use ExUnit.Case, async: true
+
+  @base_attrs %{
+    venue: :venue_a,
+    reason: {:remote, :normal}
+  }
+
+  test ".to_data/1 transforms reason to a string" do
+    event = struct!(Tai.Events.StreamTerminate, @base_attrs)
+
+    assert %{} = json = TaiEvents.LogEvent.to_data(event)
+    assert json.venue == :venue_a
+    assert json.reason == "{:remote, :normal}"
+  end
+end